Abstract
Purpose :
Inferior rectus (IR) recession, inferior oblique (IO) recession, and their combination are common operations for SO palsy. We quantified early and late misalignment correction using the Hess screen test (HST).
Methods :
We reviewed 16 patients (14 males, 2 females), age 49±21 (SD) yrs, with SO palsy confirmed by SO muscle atrophy on orbital imaging. Patients underwent either ipsilateral IO recession (N=3), contralateral IR recession (N=5), or both (N=8). HST alignment was measured in central gaze and ±15° and ±30° horizontal & vertical eccentricities, & their combinations. Manually entered HST charts were automatically digitized. Surgical misalignment correction was the difference between post- & pre-op measures at each of the 21 test fixations both early & at 3 - 7 mos follow-up.
Results :
In central gaze, early hypertropia (HT) correction was 2.8±1.1o for IO recession, 2.2±0.9o for IR recession, and 10.9±3.5° for IO & IR recession. Late central gaze HT correction was 1.1±0.9° for IO recession, 4.5±4.1° for IR recession, and 0.8±0.3° for IO & IR recession. IO recession produced the most incomitant correction, greatest in the IO field of action. IR recession produced nearly comitant correction with less magnitude than IO recession. Combined IO & IR recession created incomitant correction greatest in IO’s field of action & double that of IO recession alone. Late improvement after IO recession occurred in the SO field of action. Late HT recurrence up to 5.9±3.0o occurred in upward gaze for IR recession with or without IO recession.
Conclusions :
IO recession produces incomitant HT reduction that improves with time throughout the field of fixation. In contrast, IR recession alone or combined with IO recession is associated with HT recurrence. The largest changes in HT produced by surgery for SO palsy are in secondary or tertiary gaze positions, indicating importance of examining misalignment outside of the central gaze for assessment of outcome & progression.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.